Despite posting several deals from Green Man Gaming I've yet to purchase anything from them myself.
Bullfrog Favourites - $11.92
Dungeon Keeper™ 2
Populous™ 2: Trials of the Olympian Gods
Populous™: The Beginning
That's 75% off, or you can go for 50% off if you don't want the lot. If you already have any of the games bought on GOG, the price is lowered but you still get 75% off the rest. Some fantastic games there.
Part of their 2012 holiday sale, various other games have discounts too at the moment, with new ones every day.
Also, Duke Nukem 3D
for free, as posted by Kan Hassen here
. Only available for free for a limited time.
Little Big Bunch:
Any 5 for £6
Disciples II: Rise of the Elves Gold
Space Colony HD
Serious Sam: The Random Encounter
Tofu 1 & 2 Bundle
Trouble with Robots
Worms Reloaded is a Steam key, the rest are DRM-free. It's "powered" by GetGamesGo, hence the similarity to the GetLoadedGo deals.